Per- and polyfluoroalkyl substances (PFAS) and microplastics are two pervasive environmental contaminants, often confused. While both pose environmental concerns due to their persistence, their fundamental nature differs significantly. This article clarifies whether PFAS are microplastics and explains how these distinct entities interact within our environment.
What Are PFAS Chemicals?
PFAS, or per- and polyfluoroalkyl substances, are a large group of synthetic chemicals not found naturally. Used widely since the 1940s, they appear in many industrial and consumer products due to unique properties. Their defining characteristic is strong carbon-fluorine bonds, among the strongest in organic chemistry, contributing to exceptional thermal and chemical stability.
This stability makes PFAS resistant to heat, oil, stains, and water, leading to widespread application. They are found in non-stick cookware, water-resistant fabrics, stain-resistant carpets, food packaging, and firefighting foams. Their resistance to degradation means PFAS persist in the environment for extended periods, earning them the nickname “forever chemicals”. They can leach into soil, water, and air, leading to widespread environmental presence.
What Are Microplastic Particles?
Microplastics are small plastic particles, less than 5 millimeters (approximately the size of a pencil eraser) in length. Their small size allows them to permeate various ecosystems, including oceans, freshwater bodies, soil, and air. They are categorized into two types based on origin.
Primary microplastics are intentionally manufactured to be small, such as microbeads in cosmetics, plastic pellets, glitter, and microfibers from synthetic clothing. Secondary microplastics, the majority in the environment, originate from the fragmentation and degradation of larger plastic items. This breakdown occurs due to natural weathering processes like sunlight, wind, and waves, affecting items such as plastic bottles, bags, fishing nets, and vehicle tires.
Not the Same: Key Differences
PFAS and microplastics differ fundamentally, though both are persistent environmental contaminants. PFAS are chemical compounds, defined by their specific molecular structure and chemical composition. They are a class of thousands of individual substances, each with a unique arrangement of atoms and carbon-fluorine bonds that give them distinctive properties.
In contrast, microplastics are physical particles, fragments of plastic materials. Their identity is based on physical form, size, and the polymeric material they are made from, such as polyethylene or polypropylene. While PFAS can dissolve or become components within other materials, microplastics are solid pieces of plastic that retain their physical structure. Thus, one is a chemical entity, the other a physical particulate.
How PFAS and Microplastics Interact
Although distinct, PFAS and microplastics frequently co-exist and interact in the environment. One interaction occurs when PFAS are incorporated into plastic products during manufacturing. These chemicals are added to plastics to impart properties like water repellency, stain resistance, or non-stick surfaces. As plastic products degrade into microplastics, incorporated PFAS can leach out, spreading contamination.
Microplastic particles already present in the environment can also act as carriers for PFAS through adsorption. PFAS can attach to microplastic surfaces, effectively “hitching a ride” on these tiny particles. Studies indicate that PFAS adsorption onto microplastics can be influenced by factors like plastic type, microplastic size, and the presence of other organic or inorganic matter.
Environmental and Health Relevance
The co-occurrence of PFAS and microplastics in various environments creates implications for their transport and potential exposure pathways. Microplastics, acting as carriers, can influence how PFAS move through aquatic and terrestrial systems. This combined presence can alter their distribution, potentially spreading PFAS to areas they might not otherwise reach.
Understanding this interaction is necessary for assessing their combined environmental fate. Research suggests that combined exposure to PFAS and microplastics can lead to more pronounced effects than either contaminant alone. This highlights the complex nature of environmental pollution, where one contaminant can influence the behavior and impact of another.